DBU-mediated [4 + 2] annulations of donor–acceptor cyclopropanes with 3-aryl-2-cyanoacrylates for the synthesis of fully substituted anilines

Abstract

A facile synthesis of fully substituted anilines by the DBU-mediated [4 + 2] annulation of donor–acceptor 1,1-dicyano-cyclopropanes with 3-aryl-2-cyanoacrylate has been developed. This reaction involves a highly efficient multiple domino sequence consisting of ring opening of donor–acceptor cyclopropanes, regioselective intermolecular Michael addition, intramolecular nucleophilic addition and aromatization as key unit steps. This transformation provides a straightforward synthetic protocol for constructing fully substituted aniline derivatives. The structure of two typical products was confirmed by X-ray crystallography.